I want to apply to UCL, Biomedical engineering.

I'm a korean student in Africa, studying AS level.
Physics, chemistry, Biology, math. (planning to drop bio for A2)
So I don't get that much help of how to apply via UCAS but I do have some general knowledge about it. I've heard that the deadline to apply is 5th of january.

I really want to go to UCL to study biomedical engineering and their requirement is AAA- ABB, physics and math inclusive but A grade in math preferred.
My IGCSE grades were as follows:
Math-A(86)
Physics-A*(91)
Biology-A*(90)
Chemistry-A(87)
English-C(62)
Business studies-B(76)
Accounts-B(74)
French-D(57)

And I'm currently doing my AS level exams, and I expect my grades to be AABC or ABBC.
A in physics, A or B in chemistry, B in biology and C in math (the problem begins here).

I have been doing great in my math classes, my predicted grade for math was A for sure. But I kind of messed up my pure math although my statistics were alright, So I expect my math grades to be high C or low B. (More likely a C)

So I'm retaking math for oct/nov session but I heard that the results might not be out by 5th of january which is the deadline to apply. That means I will have to apply to UCL with my grade C in math which will make them doubt that I will achieve a good grade in A2 as I did not do very well in my AS maths.

so my questions are as follows:
1. Will UCL wait for the results of my retakes and consider it before they reply me?
2. Do they tell you to achieve specific grades to get accepted?
3. I got an A(86%) in math for IGCSE, would it help them not to underestimate me in math?
4. Will they interview me before making a decision? how? something like skype?
5. Is it likely to get accepted by UCL if I achieve A2 grades like AAB?
6. If I get an A* in A2 physics but a B in A2 math, is it likely to get accpted?